Device for centering spectacle lenses and for fastening a holding part on the lenses

Abstract

A device for centering spectacle lenses and for fastening a holding part on the lenses. The device includes a mounting base, a guide or column sleeve arranged vertically thereon, as well as a casing which is rotatable and displaceable in height, and to which a swivel arm which supports the holding part is connected. The object of the present invention is to make it possible, in a simple manner and without great structural expense and without taking a lot of time and effort, to be able to lower the holding part accurately vertically along a prescribed straight line onto the spectacle lens, so that the holding part maintains a desired precise position on the spectacle lens, and with the aid of which the lens can be inserted in an edge grinding machine. To realize this, the device is embodied such that a torque is exerted upon the casing during longitudinal movement relative to the column sleeve. As a result of this torque, a guide edge of the casing is held free of play in sliding engagement against a guide part or pin of the column sleeve.

What I claim is: 
     
       1. A device for centering a spectacle lens positioned precisely for placement thereof via a holding part on said lens, said device comprising: a mounting base;   a column sleeve arranged vertically on said mounting base and provided with a guide means;   a rotatable casing disposed around said column sleeve and provided with a guide edge; means for height adjustment of said casing relative to said column sleeve, means with which a torque is exerted upon said casing during longitudinal movement thereof relative to said column sleeve, means for holding said guide edge of said casing in sliding engagement and free of play against said guide means of said column sleeve as a result of said torque; and   a swivel arm, which is connected with said casing and supports said holding part.   
     
     
       2. A device according to claim 1, which includes a spring associated with said column sleeve, said casing being under the effect of said spring. 
     
     
       3. A device according to claim 2, in which said casing is provided with a right-angled slot which includes a circumferentially directed segment and a longitudinally directed segment, with said guide edge of said casing being formed by said longitudinally directed segment; which includes an intermediate sleeve which is provided with a longitudinal slot and is disposed between said column sleeve and said casing; in which said guide means of said column sleeve is a pin-like member which projects through said longitudinal slot of said intermediate sleeve and through said right-angled slot of said casing; in which said casing is provided with a further edge which is inclined relative to the longitudinal axis of said column sleeve; and in which said intermediate sleeve includes a radial pin which engages said further edge of said casing when the latter is pressed down against the pressure of said spring. 
     
     
       4. A device according to claim 3, in which said casing includes an inclined elongated hole which forms said further edge of said casing, said radial pin of said intermediate sleeve engaging in said elongated hole. 
     
     
       5. A device according to claim 4, in which said spring is a compression spring which is disposed between said mounting base and said casing, with the upper portion of said spring surrounding said intermediate sleeve in the lowest position of the latter. 
     
     
       6. A device according to claim 4, in which the projected length of said inclined elongated hole, as measured in the circumferential direction of said casing, corresponds at least approximately to the length of said circumferential segment of said right-angled slot. 
     
     
       7. A device according to claim 4, in which the free end of said circumferential segment of said right-angled slot is provided with a downwardly directed arresting recess. 
     
     
       8. A device according to claim 4, in which the width of said longitudinal slot of said intermediate sleeve, and the width of said longitudinal segment of said right-angled slot of said casing, correspond to the thickness of said pin-like member of said column sleeve guided in these slots, allowing for the play between said parts. 
     
     
       9. A device according to claim 1, in which said casing includes a radially outwardly directed pin; and which includes an outer sleeve which is disposed about said casing and is adapted to be rotatably driven by a motor, said outer sleeve being provided with a helical slot into which said pin of said casing engages. 
     
     
       10. A device according to claim 9, in which said casing is provided with a right-angled slot which includes a circumferentially directed segment and a longitudinally directed segment, with said guide edge of said casing being formed by said longitudinally directed segment; and in which said radially outwardly directed pin of said casing is located at least approximately opposite to said vertical, i.e. longitudinally directed, segment of said right-angled slot. 
     
     
       11. A device according to claim 10, in which said helical slot of said outer sleeve extends over at least approximately 360° of the periphery of said outer sleeve.